The CNDO-MO study of oxygen impurity states in AlN crystal

Deep levels due to oxygen impurity have been theoretically studied by the quasimolecular approach. The calculation of the orbital spectra was performed using the CNDO/2 method. Some important quantities (transition energies, width of valence band, effective charges etc.) were estimated. The results obtained agree qualitatively well with experimental data but quantitatively are still about 20% in error. Some reasons for the above discrepancy are briefly discussed.The authors are very grateful to Dr. J.Kubátová and Dr. S.Paesová for helpful discussions of the experimental investigations of aluminum nitride and to Dr. J.Pastrák for his interest in this work and discussion of results.